Extreme Weather Forty Years of the Tornado and Storm Research Organisation (TORRO)

Robert K. Doe, BA Hons. (Exon), Ph.D. (Port), FRMetS, MRI
Robert graduated with a Ph.D. from the University of Portsmouth, where he specialised in coastal storm climatology. Robert is a Director and Treasurer of The Tornado and Storm Research Organisation (TORRO). He is a Fellow of The Royal Meteorological Society (FRMetS) and Member of the Royal Institution (MRI). He was Editor-in-Chief of The International Journal of Meteorology (2002–2006) and has published research on meteorological phenomena including; tornadoes, waterspouts, floods, snowstorms, ball lightning, coastal storms, climate and risk. He is an Honorary Research Fellow in the School of Environmental Sciences, at the University of Liverpool.

Foreword xiii

Preface xv

About the Companion Website xvii

1 Researching Extreme Weather in the United Kingdom and Ireland: The History of the Tornado and Storm Research Organisation, 1974–2014 1
G. Terence Meaden

1.1 Introduction: The Early Years 1

1.2 International T]Scale: Theoretical Basis 2

1.2.1 Hailstorm Research 3

1.2.2 Temperature Extremes for the British Isles 3

1.3 Tornado Research Organisation 4

1.4 The Inaugural Issue of The Journal of Meteorology 4

1.5 Storm]Damage Site and Track Investigations 6

1.6 Birmingham Tornado of 28 July 2005 8

1.7 TORRO Conferences 8

1.8 The Future 11

Acknowledgements 13

Additional information 13

References 13

Part I Torna does 15

2 Historical tornadoes in the British Isles 17
Paul R. Brown and G. Terence Meaden

2.1 Introduction 17

2.2 Etymology of the Word Tornado 17

2.3 Terminology 18

2.4 Accuracy and Completeness of the Records 19

2.5 Analysis of Historical Tornadoes 20

2.6 Examples of Historical Tornado Reports 21

2.7 Concluding Remarks 30

References 30

3 Supercell and Non]supercell Tornadoes in the United Kingdom and Ireland 31
Matt Clark and David Smart

3.1 Introduction 31

3.2 Basic Structure and Life Cycle of a Storm Cell 32

3.3 Storm Mode: An Overview of Single]Cell, Multicell and Supercell Convection 32

3.4 Tornadoes in Supercell and Non]supercell Storms 36

3.4.1 Synoptic Situations Associated with Tornadoes in the United Kingdom 40

3.5 Towards a Climatology of Tornadoes by Synoptic Type 43

3.6 Monthly and Annual Frequencies of Tornadoes by Synoptic Type 43

3.7 Spatial Distribution of Tornadoes by Synoptic Type 44

3.8 Morphology of Tornadic Storms 46

3.9 Association of Supercells with Giant Hail 47

3.10 Case Studies of Supercell and Non]supercell Tornadoes 48

3.10.1 Case 1: The Cold Front of 29 November 2011 48

3.10.2 Case 2: The English Midlands Supercells of 28 June 2012 51

3.10.3 Case 3: The West Cornwall Supercell of 16 December 2012 52

3.11 Concluding Remarks 55

References 58

4 Tornadoes in the United Kingdom and Ireland: Frequency and Spatial Distribution 61
Peter Kirk, Tim Prosser, and David Smart

4.1 Introduction 61

4.2 The TORRO Database 62

4.3 Tornado Frequency for the United Kingdom and Ireland: 1981–2010 63

4.3.1 Annual Number of Tornadoes and Tornado Days 63

4.3.2 Season and Month of Occurrence 64

4.3.3 Hour of Occurrence 65

4.3.4 Intensities 65

4.3.5 Track Lengths 65

4.3.6 Maximum Track Widths 65

4.3.7 Directions of Travel 66

4.4 Spatial Distribution of Tornadoes in the United Kingdom and Ireland 66

4.4.1 Simple Mapping of the Database 66

4.5 Issues with Mapping 66

4.6 Kernel Density Mapping of Tornado Distribution 70

4.7 The ‘London Metropolitan’ Anomaly 70

4.8 The Isle of Wight and South Coast Anomaly 72

4.9 Concluding Remarks 73

Acknowledgements 74

Additional Information 74

References 75

5 Tornado Extremes in the United Kingdom: The Earliest, Longest, Widest, Severest and Deadliest 77
Mike Rowe

5.1 Introduction 77

5.2 Earliest Tornado 77

5.3 Other Whirlwinds (First UK Record Only) 79

5.4 Longest Tornado Track 80

5.5 Widest Tornado Track 82

5.6 Severest Tornado 83

5.7 Largest Outbreaks 88

5.8 Highest Death Toll 89

5.9 Concluding Remarks 89

Acknowledgements 89

References 89

6 Site Investigations of Tornado Events 91
John Tyrrell

6.1 Introduction 91

6.2 Getting Started: How Site Investigations Come About 92

6.3 Site Investigation Methods 92

6.4 Site Investigation Outcomes: The Growing Understanding of UK Tornadoes 94

6.5 Site Investigation Experience 101

6.6 Concluding Remarks 102

Acknowledgements 103

References 103

Part II Thunderstorms and Lightning 105

7 Epic Thunderstorms in Britain and Ireland 107
Jonathan D.C. Webb

7.1 Introduction 107

7.2 Selected Epic Thunderstorm Events 109

7.2.1 2–3 August 1879 109

7.2.2 5–10 June 1910 110

7.2.3 7–10 July 1923 114

7.2.4 17–18 July 1926 114

7.2.5 28–29 August 1930 114

7.2.6 18–22 June 1936 116

7.2.7 The West Country Thunderstorm of 4 August 1938 119

7.2.8 5 September 1958 123

7.2.9 22–24 June 1960 125

7.2.10 8–9 August 1975 125

7.2.11 13–14 June 1977 126

7.2.12 25–26 July 1985 127

7.2.13 24 May 1989 128

7.2.14 8–9 August 1992 131

7.2.15 24 June 1994 132

7.3 Concluding Remarks 132

Acknowledgements 132

References 132

8 Thunderstorm Observing in the United Kingdom: A Personal Diary of Days with Thunder 1953–2013 135
Bob Prichard

8.1 Introduction 135

8.2 Early Observations 135

8.2.1 Thunderstorm Observing 136

8.3 Thunderstorms of the 1960s 137

8.3.1 The ‘Days with Thunder Heard’ Statistic 140

8.3.2 Back to the 1960s 140

8.4 Thunderstorms of the 1970s 141

8.5 Thunderstorms of the 1980s 143

8.6 The Forecasting of Thunderstorms 145

8.7 Back to the 1980s 146

8.8 Thunderstorms of the 1990s 147

8.9 The Most Recent Thunderstorms: 2000–2013 150

8.10 Concluding Remarks 154

References 154

9 Severe Hailstorms in the United Kingdom and Ireland: A Climatological Survey with Recent and Historical Case Studies 155
Jonathan D.C. Webb and Derek M. Elsom

9.1 Introduction 155

9.1.1 Establishment of a Tornado and Storm Research Organisation Research Database of Hail Events 155

9.2 Assessing the Intensity of Hail Falls 155

9.2.1 Hailstorm Intensity Scale 155

9.2.2 Kinetic Energy 156

9.2.3 Hailstone Size and Damage 156

9.2.4 Other Factors Affecting Damage 156

9.3 Annual Frequency of Hail 157

9.3.1 All Significant, Damaging Hailstorms 157

9.3.2 Frequency of Extreme, Destructive Hailstorms 158

9.3.3 Comparisons with Continental Europe 159

9.4 Seasonal Occurrence of Hail 159

9.4.1 General Seasonal Incidence of Hail and Damaging Hailstorms 159

9.4.2 Storms of H5 Intensity or More 159

9.4.3 Comparison with the Incidence of Thunderstorms 159

9.5 Geographical Distribution 160

9.5.1 Storms of H2 Intensity or More 160

9.5.2 Geographical Distribution of Storms of H5 Intensity or More 161

9.5.3 Point Frequencies 161

9.5.4 European Comparisons 161

9.6 Hailstorm Characteristics 161

9.6.1 Hail Swathes 161

9.6.2 Radar and Hail Swathe Identification 163

9.6.3 Results of Hail Swathe Analyses 163

9.7 Synoptic Weather Types and Hailstorms 164

9.7.1 Specific Synoptic Background to Hailstorms 164

9.8 Hour]of]Day Distribution 167

9.9 Summary of TORRO’s Overall Findings 168

9.10 Twenty of the Most Severe Hailstorms 169

9.10.1 1687: The Alvanley Storm 169

9.10.2 1697: Remarkable Late Spring Storms 169

9.10.3 1763: The Great Kent Storm of 19 August 169

9.10.4 1808: The Great Somerset Hailstorm of 15 July 169

9.10.5 1818: Stronsay, Orkney, 24 July 170

9.10.6 1843: The Great Hailstorm of 9 August 170

9.10.7 1893: Northern England and Southern Scotland on 8 July 172

9.10.8 1897: The Diamond Jubilee Storm of 24 June 174

9.10.9 1915: 4 July 175

9.10.10 1935: 22 September (Sometimes Referred to as the ‘Great Northamptonshire Hailstorm’) 177

9.10.11 1958: The Horsham Hailstorm of 5 September 178

9.10.12 1959: 9–11 July (Including the ‘Wokingham Storm’) 179

9.10.13 1967: The Wiltshire Hailstorm of 13 July 181

9.10.14 1968: The ‘Dust Fall’ Storms of 1–2 July 181

9.10.15 1983: South Coast Hailstorms of 5 June 185

9.10.16 1983: Violent Hailstorms in North]West England on 7 June 185

9.10.17 1985: The Essex ‘Dunmow’ Hailstorm of 26 May 186

9.10.18 1996: The Storms of 7 June 187 9.10.19 1997: The Severe Storms of FA Cup Final on Saturday, 17 May 189 9.10.20 2012: The Destructive English Midlands Hailstorm of 28 June 191

9.11 Concluding Remarks 191

Acknowledgements 193

References 193

10 Lightning Impacts in the United Kingdom and Ireland 195
Derek M. Elsom and Jonathan D.C. Webb

10.1 Lightning as a Weather Hazard 195

10.2 Historical Research into Lightning 196

10.3 Research into Lightning Impacts 197

10.4 Annual Number of Lightning Incidents Causing Injuries and Deaths 198

10.5 Lightning Injuries 198

10.6 Electrical Routes by Which Lightning Causes Injuries 199

10.7 Lightning Strikes to Groups of People 200

10.8 Locations to Avoid during Thunderstorms 201

10.9 Lightning Incidents Affecting People Indoors 201

10.10 The Frequency with which Lightning Strikes a Person 202

10.11 Fewer Deaths from Lightning Over Time 203

10.12 Lightning Strikes to Animals 204

10.13 Lightning Impacts on Aircraft and Motor Vehicles 205

10.14 Increasing Awareness of the Lightning Risk 206

Acknowledgements 206

References 206

11 Ball Lightning Research in the United Kingdom 209
Mark Stenhoff and Adrian James

11.1 Introduction 209

11.2 Definitions 209

11.2.1 Lightning 209

11.2.2 Ball Lightning 210

11.3 What Ball Lightning Is Not 210

11.4 Ambiguity: Ball Lightning, Fireballs, Meteors and Meteorites 211

11.5 Early Beliefs about Lightning and Ball Lightning 212

11.6 Early Reports of Ball Lightning 213

11.6.1 Ball Lightning over Land 213

11.6.2 Ball Lightning over Rivers and the Sea 214

11.6.3 Ball Lightning Associated with Churches 215

11.6.4 Ball Lightning within Houses 216

11.6.5 Ball Lightning as a Precursor to Cloud]to]Ground Lightning 217

11.7 Interpreting Early Reports 217

11.7.1 1833: Early British Opinion about the Nature of Ball Lightning by Luke Howard FRS (1772–1864) 217

11.7.2 1837–1859: Surle Tonnerre and Other Works by François Arago (1786–1853) 217

11.7.3 1838: Comments on Ball Lightning by Michael Faraday FRS (1791–1867) 218

11.7.4 1842: ‘On the Nature of Thunderstorms’ by Sir William Snow Harris FRS (1791–1867) 218

11.7.5 1854–1868: English Translations of French Works 219

11.7.6 The Late 19th Century: Ball Lightning, Spiritualism and Parapsychology 219

11.7.7 1921: The Meteorological Office ‘Ball Lightning Enquiry’ 220

11.7.8 1923: Survey of Ball Lightning Reports 220

11.7.9 1870–1934: Speculations on the Nature of Ball Lightning 220

11.7.10 1936: Does Ball Lightning Exist? 220

11.7.11 1936–1937: The ‘Tub]of]Water’ Event and the Estimated Energy Content of Ball Lightning 220

11.7.12 1937–1957: Quantum]Mechanical and Nuclear Hypotheses for Ball Lightning 221

11.7.13 1955–1972: Plasma Hypotheses for Ball Lightning 222

11.7.14 1964: The Flight of Thunderbolts by Sir Basil Schonland FRS 222

11.7.15 1969: Eminent UK Scientists Report Ball Lightning in Aircraft 222

11.7.16 1969: The Taming of the Thunderbolts by C. Maxwell Cade and Delphine Davis 223

11.7.17 1971: Ball Lightning: An Optical Illusion? 223

11.7.18 1971: Micrometeorites of Antimatter? 223

11.7.19 1972–1995: Crew’s Ionised Jet]Stream Hypothesis for Ball Lightning (and Some UFOs) 224

11.7.20 1974: TORRO and the Journal of Meteorology 224

11.7.21 1976: A Close Encounter with a Fiery Ball Raises Questions of Ball Lightning Energy 224

11.7.22 Ball Lightning as Electromagnetic Radiation 224

11.7.23 Reviews of Ball Lightning 225

11.7.24 Ball Lightning Reported at Cambridge University 226

11.7.25 1985–1999: The TORRO Ball Lightning Division 226

11.7.26 1999: Ball lightning: An Unexplained Phenomenon in Atmospheric Physics by Mark Stenhoff 227

11.7.27 2002: Royal Society Theme Issue on Ball Lightning 227

11.7.28 2006: Publication of Ministry of Defence: Unidentified Aerial Phenomena in the UK Air Defence Region (2000) 227

11.7.29 2000–2014: TORRO Ball Lightning Division 228

11.8 A Selection of Ball Lightning Reports Recorded by TORRO 2000–2014 228

11.8.1 Ball Lightning inside Houses 228

11.8.2 Experienced Observer 229

11.8.3 Earthquake Ball Lightning? 229

11.8.4 A Recent Ball Lightning Event Reported to TORRO 229

11.9 2014: Ball Lightning in the UK Media 230

11.10 Concluding Remarks 230

Acknowledgments 230

References 230

Part III EXTREMES 235

12 Forecasting Severe Weather in the United Kingdom and Ireland 237
Paul Knightley

12.1 Introduction 237

12.2 Modern Forecasting 238

12.3 Severe Storm Forecasting in the United States 238

12.4 Severe Storm Forecasting Elsewhere 239

12.5 Forecasting Techniques 239

12.6 The Ingredients]Based Approach 240

12.6.1 Moisture 240

12.6.2 Instability 240

12.6.3 Lift 240

12.6.4 Wind Shear 240

12.7 TORRO’s Forecasts 241

12.8 Forecasting Severe Weather: 28 June 2012 241

12.8.1 Background 241

12.9 Concluding Remarks 245

Acknowledgements 246

References 246

13 Extreme Flooding in the United Kingdom and Ireland: The Early Years, ad 1 to ad 1300 247
Robert K. Doe

13.1 Introduction 247

13.2 Sources of Evidence 247

13.3 The Early Years – 1st–10th Centuries 248

13.4 Extreme Flooding in the 11th Century 249

13.5 Extreme Flooding in the 12th Century 250

13.6 Extreme Flooding in the 13th Century 251

13.7 Concluding Remarks 259

Acknowledgements 259

References 259

14 Extreme Rainfall and Flash Floods in the United Kingdom and Ireland: Synoptic Patterns and Selected Case Studies 261
John Mason, Paul R. Brown, Jonathan D.C. Webb, and Robert K. Doe

14.1 Introduction 261

14.2 Severe Dynamic Rainfalls 261

14.3 Hybrid Rainfalls – Dynamic Precipitation with Embedded Convective Cells 264

14.4 Severe Convective Rainfalls 269

14.5 Gwynedd, North Wales, UK, 3 July 2001 270

14.6 Boscastle, Cornwall, UK, 16 August 2004 272

14.7 Holmfirth, Yorkshire, UK, 29 May 1944 274

14.8 Ottery St. Mary, Devon, UK, 30 October 2008 278

14.9 Concluding Remarks 280

Acknowledgements 281

References 281

15 Heavy Snowfalls Across Great Britain 283
Richard Wild

15.1 Introduction 283

15.2 Definitions 283

15.3 Synoptic Systems and Heavy Snowfalls 283

15.4 Snowfall Climatology of Great Britain 284

15.5 Sources of Data 284

15.6 Snow Depths and Days with Snowfall 284

15.7 Spatial Methodology for Heavy Snowfall Events 285

15.7.1 LWT Catalogue 285

15.8 Heavy Snowfall Events over Great Britain 285

15.9 Heavy Snowfalls 1861–1869 286

15.9.1 20 February 1865 286

15.10 Heavy Snowfalls 1870–1879 286

15.11 Heavy Snowfalls 1880–1889 286

15.11.1 18–19 January 1881 286

15.12 Heavy Snowfalls 1890–1899 287

15.12.1 9–13 March 1891 287

15.13 Heavy Snowfalls 1900–1909 287

15.14 Heavy Snowfalls 1910–1919 287

15.14.1 11–12 January 1913 287

15.15 Heavy Snowfalls 1920–1929 288

15.15.1 25 December 1923 288

15.15.2 15–16 February 1929 288

15.16 Heavy Snowfalls 1930–1939 288

15.17 Heavy Snowfalls 1940–1949 288

15.17.1 26–30 January 1940 288

15.17.2 18–20 February 1941 288

15.17.3 26–27 March 1941 289

15.18 Heavy Snowfalls 1950–1959 289

15.18.1 8 February 1955 289

15.19 Heavy Snowfalls 1960–1969 289

15.20 Heavy Snowfalls 1970–1979 289

15.21 Heavy Snowfalls 1980–1989 289

15.22 Heavy Snowfalls 1990–1999 289

15.23 Heavy Snowfall Frequencies in Great Britain 1861–1999 289

15.23.1 Numbers of Heavy Snowfall Days 290

15.23.2 Mean Length (In Days) of Heavy Snowfall Events 291

15.24 LWTs and Heavy Snowfalls 292

15.24.1 LWT Frequency by Decade 292

15.24.2 LWT Frequency by Month and Season 293

15.24.3 LWT Frequencies Before, During and After the Heavy Snowfall Day 293

15.25 Depressions and Heavy Snowfalls 293

15.25.1 Depression Trajectories Associated with Heavy Snowfall Events 293

15.25.2 Depression Traffic Associated with Heavy Snowfall Events 293

15.26 Fronts Associated with Heavy Snowfall Days (1937–1999) 296

15.26.1 Geographical Variations in Meteorological Fronts 296

15.26.2 Relationship Between Fronts and LWT 297

15.27 Concluding Remarks 297

Acknowledgements 298

References 298

Appendices Appendix A: Data (Web Material)

Appendix B: Selected Pictures from Conferences and Meetings 301

Appendix C: Tornadoes in the United Kingdom and Ireland 1054–2013 319

Appendix D: Data (Web Material) Selected Name Index 321

Subject Index 323

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